Research is one of the necessary elements to build up knowledge; for this reason, the career of nutrition at Mariano Galvez University has implemented research as an important component of the course of analytical chemistry. During this process, the impact of scientiﬁc involvement is evaluated as part of a regular course and it allows students to develop a research as a product of their imagination and curiosity.

In this paper, an approach to the removal of the eriochrome black T in an actual efﬂuent (generated from the test to determine the water hardness by complexometric titration) using perlite modiﬁed with orthophenanthroline by the adsorption technique is proposed. A preliminary assessment of the removal of eriochrome black T in a synthetic efﬂuent (aqueous solution of eriochrome black T) was executed for subsequent application of the optimized conditions in actual residual water (titration residue of complexation).

History of science to teach nature of science: A strategy for initial science teacher education

This paper presents a didactic approach for initial science teacher education on the nature of science (NDC) using the history of science (HDC). This approach is developed through a reﬂective reading of stories about cases and controversies from HDC, which has been made by the authors of this work. A brief description of the stories and the methodological strategy for its implementation in the classroom are included. Also, the qualitative assessment of the participants reﬂections through a rubric with levels of progression is described.

EDUCATIONAL RESEARCH

Topics of quantum chemistry: analysis of its presentation in general chemistry text books

College students show serious difﬁculties in learning chemistry. From research in science teaching, this problem is considered to be multicausal. We will focus on one of the possible intrinsically disciplinary causes. Among the ﬁrst issues addressed in basic chemistry coursesofscientiﬁc/technologicalcareersarethosecorrespondingtoquantumchemistry. When the student approaches for the ﬁrst time these subjects only knows classic contents of physics and chemistry. While many of the terms used in both contexts are the same, the world and objects referred to in classical physics not seem to be the same that those that is cited in chemistry. The fact that it would seem that the quantum chemistry depends on physical models available of the world, it adds the complication of using classical physics concepts in a context in which they no longer seem to have the same meaning. In this paper we analyze the way in which general chemistry textbook introduced the contents of quantum chemistry. Four aspects are considered: epistemologic choice, perspective of approach, use of the history and philosophy of science, and contextualisation of relations between quantum and classical concepts. We conclude that the modes of presentation in the texts do not contribute to a better understanding of the concepts of the discipline, nor of the mode in which the scientiﬁc knowledge is developed.

EDUCATIONAL RESEARCH

Problem-based learning as a complement to traditional teaching in Physicochemistry

Physicochemistrys contents are considered as of little application in the future, and so a lot of the students direct their efforts towards a superﬁcial learning. Problem-based learning (PBL) is a methodological strategy that seeks to stimulate the need of knowing in students and it is used as a mean to acquire knowledge and apply them to solve a real or ﬁctitiousproblem.Thepurposeofthisarticleistodescribetheresultsofanexperienceinwhich PBL was used as a complement of traditional teaching in three student cohorts. Two instances of qualitative evaluation and three of quantitative evaluation were done. Results showed a high qualitative evaluation, emphasizing the students´ı satisfaction with the close integration of theoretical and practical contents. At the same time, the group quantitative achievements were very encouraging, even though the individual performance of the group members did not reﬂect the same. In conclusion, the adoption of PBL as a complement to traditional teaching is an educational investment that is fruitful at least in the short and medium term, despite the initial resistance of the students and the time and effort demanded to teachers and students.

EDUCATIONAL RESEARCH

An alternative evaluation of acid-base titrations through a simulation

Thisworkshowstheresultsofalearningexperienceonacid-basetitrations,basedon the projection of a simulation, in the context of an integrating and conceptual ﬁnal evaluation. This activity was done after the ﬁrst year university students attended theoretical, problemsolving and lab lessons and were subjected to traditional evaluation. Students were inquired about how they had identiﬁed the different materials and entities shown in the simulation and how they had established adequate conceptual links between them. In order to evaluate the results,thesamplewasdividedintwogroupsdependingonwhethertheparticipantshadapproved or not the General Chemistry mid-term evaluation. Interesting conclusions came up about what happens when students have to draw information from a simulation to solve traditional format problems.

EDUCATIONAL RESEARCH

How can we assess if Limpics is a fake? Learning to plan investigations in secondary education

This paper presents a task designed to introduce 9th grade students (14-15 years old) to planning investigations in the Chemistry laboratory. We used a context related to everyday life:anenterprisecommitteehasjustlaunchedacampaigninschoolsinwhichtheyaskstudents tohelpthemtounmaskanotherwhohasannouncedaveryefﬁcientdetergentcalledLimpics.To help students in planning the investigation, they were provided with coloured cards containing some questions. Their answers to these questions following a particular order will compose the planning. The analysis consists of examining students written designs (N=20) depending on their content and adequacy to solve the investigation. The main results point to short and little precise designs.